Matt Smith's Doctor has had three Cybermen adventures, not two; A Good Man Goes To War is missing from the tally above. Granted, we don't see the Doctor confront them himself, but it has more of a claim than including Mission To The Unknown in Hartnell's tally of Dalek stories.

Amy and Rory *do* appear in Closing Time.

Tom Baker's Doctor had 41 stories (or 42 if you include The Five Doctors), but certainly not 43 (unless you also include Shada, which your chart doesn't).

Glossing over Astrid, Adelaide, Katarina, Sara K and Kamelion (since you did specify "major" companions), K9 Mark III and the Brigadier have also both died in Doctor Who. Adric is not the only one.

Jamie and Zoe lost their memories of their TARDIS travels, but not of the Doctor himself.

John Simm's Master is not the only villain to receive second billing on the show (although he is the only one to do so in the *opening* credits). The Hartnell, Troughton and early Davison years often credited villains above companions (Monarch being a prime example).

Series vs. Season is more to which side of the Pond you live on. Americans (in general) refer to a given run as a Season, to match what we have with American television. Over in the UK (and several other places, probably also Canada) refer to a given run as a Series. Which generation of the show (New vs. Old) isn't actually the dividing point.

That said, I have noticed several folks in the fandom correct themselves to "Series" instead of "Season" when referring to the newer generation.